Impaired hoarding and olfactory learning in DSP-4-treated rats and control cagemates

The possibility that variables affecting rats' home-cage odor preferences also influence hoarding behavior was examined. Neonatal male rats were injected SC with the noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4), or with vehicle. At weaning, rats were assigned to control-only, DSP-4-only, or mixed groups of DSP-4 and control rats. For the next 10 days, half the rats in each social condition were housed in cedar shavings, and remaining rats were housed in pine. Exposure to cedar significantly increased preference for the odor in control-only groups, but not in DSP-4-only or mixed treatment groups. Control-only groups also hoarded significantly more pellets per animal than rats in the other two social conditions. The results suggest that both olfactory adaptation and hoarding can be impaired by either neonatal NE depletion or an abnormal social environment.